Welcome to MySwissAlps! Each person needs his own pass. For the Swiss Half Fare Card, for example, simply click to one of the websites selling it (see myswissalps.com/ swisshalffarecard/ price please), and enter the number of travelers when asked.

The Swiss Card does not exist anymore, by the way.

I noticed you're from the Netherlands so you can post your questions to the Dutch forum if you want: myswissalps.com/nl/ forum.